Modern computer systems are often controlled by programs (e.g., software and/or firmware), which may be packaged with the computer systems when shipped. Unfortunately, most programs, even those encapsulated as firmware, are relatively easy to change and/or swap out (e.g., by unauthorized manufacturers or distributors). Thus, computer systems designed for a specific purpose may be modified to perform unintended operations, which may reflect negatively on the manufacturer of the computer system. Moreover, it may prevent clients from receiving the computer systems that they are expecting. To combat this, manufacturers of central processing units have begun placing security measures in their chips, but even these have been thwarted by the surreptitious replacement of the processors.